离散频率编码波形是一类常用的多输入多输出雷达波形,加入线性调频能够改善其自相关性能。将基于遗传算法和模拟退火的混合算法用于离散频率编码线性调频(discrete frequency coding waveform-linear frequency modulation,DFCW-LFM)波...离散频率编码波形是一类常用的多输入多输出雷达波形,加入线性调频能够改善其自相关性能。将基于遗传算法和模拟退火的混合算法用于离散频率编码线性调频(discrete frequency coding waveform-linear frequency modulation,DFCW-LFM)波形的优化设计,仿真结果表明,用该优化算法得到的信号其相关性能要优于现有方法。另外,提出了一种改进的DFCW-LFM波形设计方法。该方法在DFCW-LFM波形的基础上,对频率编码子脉冲同时进行相位编码,构成DFCW-LFM和相位编码的混合波形,并采用混合算法对其进行优化设计。仿真结果表明,和已有的DFCW-LFM波形相比,所设计混合波形的相关性能得到了进一步改善。展开更多
We introduce the entangled state representation to describe the four-wave mixing.We find that the four- wave mixing operator,which engenders the correct input-output field transformation,has a natural representation i...We introduce the entangled state representation to describe the four-wave mixing.We find that the four- wave mixing operator,which engenders the correct input-output field transformation,has a natural representation in the entangled state representation.In this way,we see that the four-wave mixing process not only involves squeezing but also is an entanglement process.This analysis brings convenience to the calculation of quadrature-amplitude measurement for the output state of four-wave mixing process.展开更多
Using the extended Blonder-Tinkham-Klapwijk formalism, we investigate the conductance spectra of normal metal/dx2-y2 ＋ idxy mixed wave superconductor graphene junctions. It is found that the conductance spectra vary ...Using the extended Blonder-Tinkham-Klapwijk formalism, we investigate the conductance spectra of normal metal/dx2-y2 ＋ idxy mixed wave superconductor graphene junctions. It is found that the conductance spectra vary strongly with the orientation of the gap and the amplitude ratio （Δ1/Δ0） of two components for dx2-y2 ＋ idxy mixed wave. The zero bias conductance is nearly 2 and the conductance peak vanishes in doped graphene for a = 0 and Δ1/Δ0 = 1. The conductance increases with increasing the amplitude ratio of two components for α =π/4 and Δ1/Δ0 -- 1. The ZBCP becomes observable wide with 1 〈 EF/Δ0 〈 100 for α= π/4 and Δ1/Δ0 = 1. This property is different from that in normal metal/dx2-y2 wave superconductor graphene junctions.展开更多
As an advanced generation instrument of earth observation,small footprint full waveform light detection and ranging(LiDAR) technology has been widely used in the past few years.Decomposition and radiative correction i...As an advanced generation instrument of earth observation,small footprint full waveform light detection and ranging(LiDAR) technology has been widely used in the past few years.Decomposition and radiative correction is an important step in waveform data processing,it influences the accuracy of both information extraction and further applications.Based on a stepwise strategy,this study adopts Gaussian mixture model to approximate the LiDAR waveform.In addition to waveform decomposition,a relative correction model is proposed in this paper,the model considers the transmit pulses as well as the different of the travel path for implementing LiDAR waveform relative correction.Validation of the stepwise decomposition and relative correction model are carried out on LiDAR waveform acquired over Zhangye,China.The results indicate that stepwise decomposition identified the number of peaks in LiDAR waveforms,center position and width of each peak well.The relative radiometric correction also improves the similarity of waveforms which acquired at the same target.展开更多
文摘离散频率编码波形是一类常用的多输入多输出雷达波形,加入线性调频能够改善其自相关性能。将基于遗传算法和模拟退火的混合算法用于离散频率编码线性调频(discrete frequency coding waveform-linear frequency modulation,DFCW-LFM)波形的优化设计,仿真结果表明,用该优化算法得到的信号其相关性能要优于现有方法。另外,提出了一种改进的DFCW-LFM波形设计方法。该方法在DFCW-LFM波形的基础上,对频率编码子脉冲同时进行相位编码,构成DFCW-LFM和相位编码的混合波形,并采用混合算法对其进行优化设计。仿真结果表明,和已有的DFCW-LFM波形相比,所设计混合波形的相关性能得到了进一步改善。
基金supported by the President Foundation of the Chinese Academy of Sciences and National Natural Science Foundation of China under Grant No.10775097
文摘We introduce the entangled state representation to describe the four-wave mixing.We find that the four- wave mixing operator,which engenders the correct input-output field transformation,has a natural representation in the entangled state representation.In this way,we see that the four-wave mixing process not only involves squeezing but also is an entanglement process.This analysis brings convenience to the calculation of quadrature-amplitude measurement for the output state of four-wave mixing process.
基金Supported by the National Natural Science Foundation of China under Grant No. 11074088
文摘Using the extended Blonder-Tinkham-Klapwijk formalism, we investigate the conductance spectra of normal metal/dx2-y2 ＋ idxy mixed wave superconductor graphene junctions. It is found that the conductance spectra vary strongly with the orientation of the gap and the amplitude ratio （Δ1/Δ0） of two components for dx2-y2 ＋ idxy mixed wave. The zero bias conductance is nearly 2 and the conductance peak vanishes in doped graphene for a = 0 and Δ1/Δ0 = 1. The conductance increases with increasing the amplitude ratio of two components for α =π/4 and Δ1/Δ0 -- 1. The ZBCP becomes observable wide with 1 〈 EF/Δ0 〈 100 for α= π/4 and Δ1/Δ0 = 1. This property is different from that in normal metal/dx2-y2 wave superconductor graphene junctions.
基金supported by Major State Basic Research Development Program of China(Grant No.2007CB714406)National Key Technology R&D Program of China(Grant No.2008BAC34B03)
文摘As an advanced generation instrument of earth observation,small footprint full waveform light detection and ranging(LiDAR) technology has been widely used in the past few years.Decomposition and radiative correction is an important step in waveform data processing,it influences the accuracy of both information extraction and further applications.Based on a stepwise strategy,this study adopts Gaussian mixture model to approximate the LiDAR waveform.In addition to waveform decomposition,a relative correction model is proposed in this paper,the model considers the transmit pulses as well as the different of the travel path for implementing LiDAR waveform relative correction.Validation of the stepwise decomposition and relative correction model are carried out on LiDAR waveform acquired over Zhangye,China.The results indicate that stepwise decomposition identified the number of peaks in LiDAR waveforms,center position and width of each peak well.The relative radiometric correction also improves the similarity of waveforms which acquired at the same target.
